Problem: Express this product in scientific notation: $(2.90\times 10^{-1})\times (7.00\times 10^{-2})$
Start by collecting like terms together. $= (2.90\times 7.00) \times (10^{-1}\times 10^{-2})$ When multiplying exponents with the same base, add the powers together. $= 20.3 \times 10^{-1\,+\,-2}$ $= 20.3 \times 10^{-3}$ To write the answer correctly in scientific notation, the first number needs to be between $1$ and $10$ . In this case, we need to move the decimal one position to the left without changing the value of our answer. $ $ We can use the fact that $20.3$ is the same as $2.030 \times 10$ $ = {2.030 \times 10} \times 10^{-3} $ $= 2.030\times 10^{-2}$